Table 11 Neuroprotheses post-SCI

Author Year


Research Design


Total Sample Size

Methods Outcome

Kilgore et al., 2018




Population: Mean age=37 yr; Gender: males=10, females=3; Time since injury: 5.5 yr; Level of injury: C5 – C6.

Intervention: A surgically implanted myoelectrically-controlled neuroprosthesis was evaluated in 15 arms in individuals with cervical-level spinal cord injury. Outcome measures were assessed at baseline, one and three mo following surgery.

Outcome Measures: Active range of motion; Grip strength; Ability to pick up and release objects.

1.     Stimulation produced active extension and flexion for all five digits in all 15 arms studied, however, no statistics were reported. No subject had any active movement in their fingers or thumbs when the stimulation was turned off.

2.     There was a significant increase in grip strength when the neuroprosthesis was turned on for all individuals (p<0.0001).

3.     Using the neuroprosthesis, all 15 arms could manipulate at least 5 out of 6 objects, whereas only one hand could manipulate 4 objects prior to implantation.

Kilgore et al., 2008




Population: Mean age: 34.0±9.5 yr; Level of injury: C5=1, C6=2.


Intervention: A second generation neuroprosthesis system was implanted into individuals and functional outcomes were evaluated.

Outcome Measures: Grasp and Release Test (GRT), Activities of Daily Living Abilities (ADLAT), Craig Handicapped Assessment and Reporting Tool (CHART), NP Usage Survey.

1.     Functional Outcomes: all three subjects used their NP to perform activities that they could not perform prior to implantation (post implant follow up ranged from 2-4 yr).

2.     Body Structures and Function: every subject improved in pinch force strength; post op pinch force with the NP was significantly greater than without the NP (paired-sample t-test, p=0.038).

3.     Activities: every subject was able to double the number of objects manipulated in the GRT with NP (two subjects completed 6/6 tasks; one subject 5/6 tasks)

4.     ADLAT all three subjects improved in least five activities with one subject in all nine.

5.     Participation: all three subjects increased their scores for physical independence, one in the mobility task, one in the social integration scale, one subject a decrease in occupation subscale.

6.     Device Usage: 2/3 reported daily usage of the NP; 1/3 used the device 50% of the time.

Peckham et al., 2001



NInitial=51; NFinal=50

Participants: Age: 16-57 yr; Gender: males=42, females=9; Level of injury: C5-C6; Mean time since injury: 4.6 yr.

Intervention: Participants were trained to use the neuroprosthesis and to use it for functional activities. Once they were satisfied with their ability to perform daily activities or when they reached a plateau in proficiency then rehab was complete.

Outcome Measures: Pinch strength, active ROM, Grasp-Release Test, Activities of Daily Living (ADL) Abilities Test, ADL Assessment Test & user satisfaction survey.

1.     When the neuroprosthesis was activated all participants increased their pinch force in lateral pinch (p<0.001) and some increased their pinch force in palmar grasp (p<0.001).

2.     98% of participants moved at least one object with the neuroprosthesis (p<0.001) and 37 improved by moving at least three more objects (p<0.001).

3.     Disability was reduced in 49 of 50 participants as measured by the ADL abilities or ADL assessment tools.

Taylor et al., 2001



NInitial=9; NFinal=8

Population: Age: 31-48 yr; Gender: males=7, females=1; Level of injury: C4-6; Time since injury=43-430 mo; Follow-up time=8-53 mo.

Intervention: Interviews- reviewing use of Neuro Control Freehand System.

Outcome Measures: Amount of Care & The System.

1.     No statistical results reported

2.     Completion of personal care was provided by outside nursing agencies. (mean 11.5 hr/day, range 3-24 hr); four users had additional care from family members (mean 3.4 hr/day, range 2-5 hr); no users claimed that care given by family members had decreased

3.     System-donning external components 5-10 min; most users reported no significant problems fitting the external equipment; two users had problems locating the coil; three locating the shoulder controller; one had persistent problems maintaining the position through the day due to the adhesive tape used becoming detached (four reported this as an occasional problem); four users had problems with skin allergy to the tape or double sided adhesive rings; two users reported that the system made transfers more difficult; three users never stopped using the system due to system failure; some problems with equipment reliability; no change in paid caregiver time; six users felt more
confident when using the system; seven felt their quality of life had improved.



Carroll et al., 2000






Population: Mean age: 29.1 yr; Gender: males=4, females=2; Level of injury: tetraplegia; Time since injury: 1.2-11.3 yr.

Intervention: The Freehand System – an implanted multichannel neuroprothesis.

Outcome Measures: Pinch forces, Grasp and Release Test (GRT), Activities of Daily Living (ADL) Test.



1.     There was significant improvement in lateral pinch and palmar grasp force after rehabilitation with and without the neuroprothesis.

2.     Force differences were not found between presurgery and rehabilitation without neuroprothesis.

3.     With neuroprothesis, subjects could grasp, move and release more items in the 30 sec GRT, as compared to without the neuroprothesis.

4.     In 35/48 ADL events, less assistance was used (physically or assistive equipment) with the neuroprosthesis. In 41/48 ADL events, neuroprosthesis use was preferred in all subjects.

5.     After study, 5/6 subjects still used neuroprosthesis daily.

Mulcahey et al., 1997 USA



Population: Age: 16-18 yr; Level of injury: C6=5, Time since injury: >1yr.

Intervention: Implanted Freehand System.

Outcome Measures: Grasp Release Test, Activities of Daily Living (ADL).

1.     40 electrodes implanted, 37 continued to work, all implant stimulators have functioned without problems with follow up ranging between 16-25 mo.

2.     Grasp Release Test-lateral pinch and palmar grasp forces – Wilcoxon test, FES forces were significantly greater than tenodesis forces for both grasps (p=0.043).

Mulcahey et al., 2004


Case Series


Population: Age: 13-16 yr; Level of injury: tetraplegia; Time since injury: 4-16 wk.

Intervention: The following muscles were implanted with intramuscular electrodes: Extensor digitorum profundus, extensor pollicis longus, flexor pollicis longus, adductor pollicis, and opponens pollicis for each subject.

Outcome Measures: Muscle Strength-Pinch Force & Hand Function, Performance of Activities of Daily Living (ADL), Satisfaction with + without the Freehand System (Canadian Occupational Performance Measure (COPM)), Upper Extremity Capacity, Quadriplegic Index of Function.

1.     No statistical results reported.

2.     No perioperative complications reported.

3.     Subjects began Freehand System use between 2-5 days after implantation.

4.     Muscle Strength-no subject gained significant strength in any key muscle on their freehand limb.

5.     Pinch Force-with Freehand System – each subject realized significant improvement in pinch force.

6.     Upper Extremity Capacity-first 11 questions – no difference with or without Freehand-last set of questions Freehand System improved scores.

7.     Quadriplegic Index of Function-all subjects increased their level of independence.


8.     Freehand System Open-ended Questions-all subjects would repeat implantation.

Alon & McBride 2003




Population: Gender: males=7, females=0; Level of injury: C5-C6; Mean time since injury: 6 mo.

Intervention: Subjects practiced with the neuroprothesis daily to regain grasp, hold, and release ability and to restore selected functions of 1 of the 2 paralyzed hands. Subjects were observed 2-3x/wk for 3 wks.

Outcome Measures: Activities of Daily Living (ADL) tasks, Hand impairment measures (two grasp and release tests).

1.     All were 100% successful in using the handmaster in the studied ADL and grasp (hold and release) tasks.

2.     Improvements were noted in strength (0.57±98N to 16.5±4.4N, finger linear motion (0.0cm to 8.4±3.2cm) and Fugi-Meyer scores (p<0.05).

Hobby et al., 2001




Population: Age: 16-55 yr; Level of injury: tetraplegia.

Intervention: The patients, using an external stimulator, built up the muscles strength in the hand and forearm, to ensure the muscles were in good condition at the time of surgery.

Outcome Measures: Grip Strength, Activities of Daily Living (ADL).



1.     7/9 use Freehand System daily.

2.     Provided an active grip of some strength which allowed many functional activities.

3.     Increase in self-confidence.

4.     For over 80% of their selected ADL goals, user preferred to be independent with their Freehand system than use previous method or have activity performed by caregiver.

Snoek et al., 2000



NInitial=10; NFinal=4

Population: Age: 20-65 yr; Gender: males=8, females=2; Level of injury: C4 to C6; Classification: 3-Cu=3, 1-O=5, 2-O=1, 0-O=1; Fitted hand: Right n=6, Left n=4.

Intervention: Training for use of Handmaster.

Outcome Measures: Not specified.

1.     Six people left the study for various reasons (>50%). Over all the four remaining were able to perform several tasks with the Handmaster that they were not able to without it (i.e., 3/4 were able to put the splint on independently).

Mangold et al., 2005


Case Series


Population: Age: 15-70 yr; Gender: males=9, females=2; Level of injury: C5-C7; Severity of injury: AIS A-D.

Intervention: FES was carried out with a stationary stimulation system and two portable systems (ETHZ-Paracare FES system, and Complex Motion).

Outcome Measures: Videos of functional tasks: hand function tests, Self-designed functional tests, Follow-up query-assessment of muscle strength.

1.     Cervical SCI patients can benefit from transcutaneous FES of hand muscles during rehabilitation with respect to muscle strengthening, facilitation of voluntary muscle activity and improvements of ADL functions.

2.     Surface FES system is more flexible in its application and does not need surgical procedures.

3.     High flexibility in electrode placement, stimulation programmes, and FES control devices is required in order to adapt the system to individual needs.

Memberg et al., 2003


Case Series


Population: Level of injury: C5-C6.

Intervention: Epimysial or intramuscular electrodes were implanted on the triceps. Following surgery standard stimulation exercise regimens were followed.

Outcome Measures: Elbow extension moments at different elbow positions, Performance in controllable workspace experiments, Comparison to an alternative method of providing elbow extension in these individuals (posterior deltoid to triceps tendon transfer).

1.     Variation in elbow moment across subjects significantly greater than the variance within subjects (ANOVA p<0.001).

2.     10/11 elbows tested elbow moment generated by triceps stimulation at different elbow angles, elbow moment weakest with elbow in more extended position (30º flexion) and peaked with elbow at 90º flexion, significant ANOVA p<0.001.

3.     Elbow moment generated by triceps stimulation at 90º and 120º elbow flexion was significantly greater than elbow moment produced by tendon transfer (ANOVA p<0.05), no difference between elbow extension methods at 30º elbow flexion.

4.     Triceps stimulation and posterior deltoid together provided a greater elbow moment than each method separately, difference significant at each elbow position p<0.05, except at 90º.

5.     Quantitative workspace assessment done on 5 arms, more successful with triceps stimulation, significant for each subject, chi square p<0.05).

6.     Average acquisition time with triceps stimulation less than without stimulation 4/5 arms (3.2-6.4 seconds) and significant in 3/5 arms (unpaired t-test p<0.01) and not for one p=0.076.

Taylor et al., 2002


Case Series


Population: Mean age: 38.4 yr; Gender: males=7, females=1; Level of injury: C4-C6; Mean time since injury: 10.1 yr.

Intervention: Assessment of the Freehand System.

Outcome Measures: Grasp Release Test, Grip Strength, Activities of Daily Living (ADL), Sensory ability (static 2 pt discrimination).


1.     Grasp release test results: increase in the types of tasks that subjects could perform (pre n=1.4) and post implantation (n=5.1 p=0.011).

2.     One-yr post implantation the types of tasks performed was 5.5 p=0.027, without the system it was 1.2 (p=0.028).

3.     Number of repetitions increased post implantation from 12.7 to 37.4 (p=0.028) and without the implant post-implantation (20.2, p=0.046).

4.     At one-yr number of repetitions was increase to 50.5, p=0.046 with the system and without 24.3, p=0.28.

Bryden et al., 2000


Case Series


Population: Age: 23-48 yr; Level of injury: C5-C6.

Intervention: Participants were implanted with an upper extremity neuroprothesis including a triceps’ electrode to provide stimulated elbow extension. Participants exercised triceps 4-6 hr/session using a programmed electrical stimulation exercise regimen that includes breaks. Participants exercised either nightly or every other night-whatever was best for maintaining an optimal amount of strength.

Outcome Measures: Five overhead reaching tasks, Amount of assistance required to complete the task, Survey of home use.

1.     No statistical analysis was completed.

2.     Passive elbow extension was within normal limits.

3.     With stimulated triceps subjects attained full elbow extension; without it full range was not met.

Wuolle et al., 1999


Case Series

NInitial=42; NFinal=30

Population: Age: 13-53 yr; Gender: males=26, females=8; Level of injury: tetraplegia; Follow-up time: 1 yr.

Intervention: Implemented with a hand neuroprosthesis that provides grasp and release.

Outcome Measures: Standardized test of grasp and release (GRT), Measurements of pinch strength and range of motion, Satisfaction survey, Activities of Daily Living (ADL) survey.



1.     General Satisfaction: 87% were positive agree or strongly agree, 97% would recommend neuroprosthesis to others, 90% were satisfied with neuroprosthesis, 90% stated neuroprosthesis was reliable, 87% would have surgery again, 80% felt the neuroprosthesis met their expectations, & 77% would pay for the neuroprosthesis if they had the money.

2.     Life Impact: 88% responses were positive for life impact; 90% stated neuroprosthesis improved their quality of life; 87% positive impact on their life (90% reported did not make a negative impact); 83% provided a benefit ADL; 87% responses regarding changes in ADL were positive; 93% participants could perform ADL easier; 93% could perform ADL such as painting and shaving; 90% had increased confidence when performing ADL; 83% could perform ADL more normally; 73% could perform ADL faster.

3.     Independence: 81% of responses were positive; 87% reported they were able to function more independently; 83% used less adaptive equipment; 87% required less assistance from others; 67% felt more comfortable out in the community alone.

4.     Occupation: 57% of responses to occupation questions were positive

5.     Appearance: 87% felt their hand appearance was unchanged or improved.

6.     Usage: used prosthesis median of 5.5 days/wk – ranged from 15 participants (44%) who donned the neuroprosthesis 7day/wk to five participants (15%) who used it less than one day/wk; 24/34 participants (71%) used it ≥4 day/wk; range of usage C4/C5, C5/C5, C6/C6 levels was the same (0-7 day/wk) C5/C6 group – used it most regularly 4-7 day/wk with most participants 8/10 reporting daily use.

7.     Activities: most frequently reported activities included eating, drinking, shaving, brushing teeth, brushing hair, writing, operating a computer, playing games.

8.     Quality of Life: 18/34 positive comments; 1/34 responded neutrally; 1/34 responded negatively.

9.     Improvements: Additional stimulus channels, an implanted command source, smaller, lighter external control unit – easier to don, improve
hand and arm function, make device operable if user is confined to bed.

Kilgore et al., 1997


Case Series


Population: Age: 28-57 yr; Level of injury: C5-C6; Severity of injury: complete; Time since injury: 2-9 yr.

Intervention: Implanted neuroprosthesis.

Outcome Measures: Grasp force, Grasp-Release Test, Tests of Activities of Daily Living (ADL) (functional independence), Usage Survey.

1.     Pinch force ranged from 8 to 25N, with stimulation and greater than tenodesis grasp alone.

2.     All demonstrated functional grasp patterns and were able to manipulate at least three more objects with the neuroprosthesis; had increased independence and were able to use the neuroprosthesis at home on a regular basis; the implanted stimulator proved to be safe and reliable.

Smith et al., 1994


Case Series


Population: Age: 13-19 yr; Gender: males=5; Level of injury: C5-C6; Time since injury: 3-72 mo.

Intervention: Intramuscular electrodes were implanted in the upper extremity muscles (Freehand System).

Outcome measures: Breslow test.


1.     No predicted difference between electrodes in intrinsic and extrinsic muscles (p=0.93).

2.     Significant differences were predicted between exit sites (p=0.016) + across muscle groups (p=0.047).

3.     Survival likelihoods poorer for electrodes exiting dorsally.

4.     At 90 days after implant survivals probabilities of the finger + thumb extensors + thumb abductors were no significant than that of thumb adductor + flexor muscle groups.

Smith et al., 1996


Case Series


Population: Age: 13-19 yr; Gender: males=3, females=2; Level of injury: C5=5; Time since injury: 3-72 mo.

Intervention: Implanted Freehand System and tendoesis.

Outcome Measures: CWRU Hand System (Case Western Reserve University), Grasp and Release Test.

1.     With the implanted system and tenodesis each case of improved performance in later sessions was significantly better as compared to the initial session. (p<0.05).

2.     The average grasp forces with FNS increased; the range was from 8.9N (SD+5.2) to 22.5N (SD+8.6) and the palmar grasp forces increases from 2.1N (SD+2.9) to 11.1N (SD+6.0).